A trend in the computer industry is to servers having multiple components such as power supplies, fans and PCI cards, for example, a four-way server which has four redundant components inside and an eight-way server containing eight redundant components. An advantage of these servers is that if one component in a server goes down, the server can still keep running, e.g., a user can replace a defective electronic card or other component using "hot swapping" without crashing the system.
State-of-the-art electronic card supports normally retain one card at a time and may require screws or rivets for attachment. A screw implementation is disadvantageous in a hot-swap system because too much time is required to remove/replace the screw, and there is a danger that the loosened screw could fall onto powered components to result in an electrical disaster. One disadvantageous PCI card retainer which eliminates the need for removing/replacing the screw for installing or removing an electronic card is lever actuated and relies on friction to retain the card. This design has snap features for installation, but requires one retainer for each individual PCI card. The known retainer also does not block vertical travel of the card in the case the computer box is dropped upside down or otherwise subjected to shock or vibration. This problem is particularly acute with longer and heavier electronic cards, e.g., in supporting standard full-length PCI cards, particularly in systems which must be resistant to shock and vibration.